1. Field of Invention
The invention relates to a computer switching device and, in particular, to a computer switch for multiple chaining and the transmission method thereof.
2. Related Art
With the rapid development in information technology, computers and their peripherals become very popular. Computer users often use the mouse and keyboard to control the computers. Through the monitors or speakers, the computer users can monitor the state of the computers. Sometimes a user may have more than one computer to process different types of things. Traditionally, each computer is equipped with one set of input/output (IO) peripheral devices, including the keyboard, mouse, monitor, and speakers. However, this is a waste of money and space if one has several computers.
On the other hand, large system businesses or enterprise internal networks often involve tens to thousands servers. Each server needs a monitor, a keyboard and a mouse to for management. In practice, one rarely needs to manipulate these devices. Most of the time, the servers do not need to be controlled by the manager. In this situation, it is totally unnecessary, costly, and wasting the space to have a set of IO peripheral devices for each server.
Therefore, a keyboard video mouse (KVM) switch is proposed to use at least one set of operation device to manage several computers. Using the KVM switch does not only solve the cost problem, it simultaneously solves the problems of equipment and space. It may also conquer the compatibility problem among different interfaces.
Currently, most of the single or multiple KVM switches on the market use the CAT5, personal system/2 (PS/2) or universal serial bus (USB) interface for transmissions. Moreover, it is not easy to connect conventional KVM switches together. When several manipulating devices simultaneously access multiple computers, the signal of each operation device has to be sent out in order. Therefore, it is likely to have the signal delay problem, seriously reducing the efficiency of the whole system.
The above-mentioned two drawbacks cause a lot of inconvenience for the users. For large system businesses or the internal networks of mid-size enterprises, in particular, if the KVM switches cannot simultaneously support a large number of manipulating devices and computers, they do not only increase the costs for constructing and maintaining the system but also reduce the communication efficiency of the whole network.